Operators of this high-tech facility in South Korea say it is the world’s first indoor vertical farm built in a tunnel.

It’s also the largest such farm in the country and one of the biggest in the world, with a floor area of 2300sqm, nearly half the size of an American football field.

Camera IconA set of bright blue doors cover the entrance of the tunnel that holds a high-tech farm in South Korea.Picture: AP

Indoor vertical farming is seen as a potential solution to the havoc wreaked on crops by the extreme weather linked to climate change and to shortages of land and workers in countries with ageing populations.

The tunnel, about 190km south of Seoul, was built in 1970 for one of South Korea’s first major highways.

Once a symbol of the country’s industrialisation, it closed in 2002.

An indoor farming company rented the tunnel from the government last year and transformed it into a “smart farm”.

Instead of the chirrups of cicadas, Claude Debussy’s Clair de Lune resonates in the tunnel in hopes of stimulating the crops’ healthy growth.

“We are playing classical music because vegetables also love listening to music like we do,” said Choi Jae Bin, head of NextOn, the company that runs the vertical farm.

Camera IconHead of NextOn Choi Jae Bin explains how his high-tech tunnel-based vertical indoor farm NextOn in Okcheon, South Korea, could be a potential solution to the havoc wreaked on crops by the extreme weather linked to climate change, and to shortages of land and workers as the country ages.Picture: AP

Sixty types of fruits and vegetables grow in optimised conditions using NextOn’s own growth and harvest systems.